RAPID CITY, S.D. (AP) - A Christian evangelist in the Rapid City area is suing the South Dakota School of Mines and Technology, saying the school infringed on his right to free speech by not allowing him to preach in open areas around campus.

The Tennessee-based Center for Religious Expression filed the federal lawsuit on Mark Gavin's behalf. It says the school considered his preaching to be commercial speech rather than religious speech and told him he must pay $50 for an area inside the student union. Gavin wants to preach outside of the center.

Gavin declined comment to local media. A statement from the School of Mines said school policy is not to comment on pending litigation.